TECHNICAL

TECHNICAL

Details & Fin Primer

Explanations

This section will introduce some of the terms we use in describing the design of our fins. As well as technical details on the materials and methodologies used in the construction of the fins.

A FIN PRIMER is also found on this page. It provides a lot of detail on different types of fins setups and how they affect a board.



FLIP TIPS

WTF, XTC, DS, and WF2 designs utilize these tips

FLIP TIPS are the term we use for the unique design of the tip extensions added to some of our fins. These tips add significant performance enhancements to the fins.

FLIP TIPS
FLIP TIPS

FLIP TIPS are set at between 14º - 16º angle (outboard) to the blade of the fin, and provide a couple of important attributes to the performance of the fin.

Due to the hollow foils on the inside faces of the fins design that utilize these tips. The addition of the flip tip improves the efficiency of these inside foils. This is accomplished by allowing the hollow foil to extend all the way to the tip. Making the unflipped portion of the fin a lot more efficient.

The tips themselves also have a slight hollow foil on the inside face to improve their efficiency and to better couple with the foil in the blade.

One of the most important attributes of these tips is how they allow the board to transition through turns. If you visualize these fins in use you can see that as the board transitions more to the rail the tips of the engaged fins become more vertical in the water.

Not only does this improve the feel of the fin, but it more importantly helps the board come around during the turn, as it provides some thing to pivot around. All of this is done without losing any speed!

The illustration above shows the WF2-S fin and the shape of the flip tips. These tips do not alter the outline of the fin and are only noticeable when viewed from the front or back.

Very hard to describe how they feel and work but once you try them there is no going back, there is something magical about them!

Currently, the following HRD-KORE fins feature FLIP TIPS - WF2-S (Split keels front fin), DS-400, WTF-425 and XTC range.

FLIPTWO TIPS

Q2, Q5, and WF2 designs will utilize these tips

FLIPTWO tips are the term we use for the new, refined design of our tip extensions. These tips add subtle performance enhancements to the fins.

FLIPTWO Tips
FLIPTWO Tips

FLIPTWO tips are flipped between 4º – 6º angle (outboard) to the blade of the fin, and provide a couple of important attributes to the performance of the fin.

Due to the hollow foils on the inside faces of the fin designs that utilize these tips, the addition of the flip improves the efficiency of the inside foils. This is accomplished by allowing the hollow foil to extend all the way to the tip. Making the unflipped portion of the fin a lot more efficient.

The tips themselves also have a slight hollow foil on the inside face to improve their efficiency and to better couple with the foil in the blade. Compared to the older versions the newer tips are significantly thinner reducing the chance of cavitation.

One of the most essential attributes of these tips is how they allow the board to transition through turns. If you visualize these fins in use, you can see that as the board transitions more to the rail, the tips of the engaged fins become more vertical in the water. Not only does this improve the feel of the fin, but it more importantly helps the board come around during the turn, as it provides something to pivot around. All of this is done without losing any speed! This newer, refined version is a little more subtle than the previous versions, but still has similar characteristics.

The photo above shows the WF2-400F fin and the angle of the flip tips. These tips do not alter the outline of the fin and are only noticeable when viewed from the front or back.

This newer version enables this style of tip to be added to some of our CNC machined fins. The older style tips would not have been possible due to the panel thickness required to accommodate the flip.

Currently, the following CNC fins will feature FLIPTWO tips – WF2-400F (Split keels front fin), Q2-500FT, Q5-500 and F8 range.

TECHNICAL DETAILS

About foils and construction materials

FOILS

Foils obviously play a crucial role in the design of a fin and can dramatically impact the performance. Most of our foils are loosely based around the NACA 00 series of wing sections that are ideal for fins.

REGULAR FOILS

We pay careful attention to the foils used on all our fins. We try to match the best foil for the characteristics of the fin and wherever possible we try to keep the regular foils nice and thick for maximum efficiency.

HOLLOW FOILS
Foil Drawing
Foil Drawing

HANALEI FINS are unique in that we have perfected the use of inner hollow foils on the inside faces of most of our fins. We use these foils to increase performance and efficiency. In many cases we also couple these foils with twists and turns in the trailing edge of the fin to better manage the ejection of water from the foils. These foils have a dramatic impact on the overall performance of our fins, but in particular to the speed! Our term for these inside foils is HOLOFOILS!

PHAT FOILS
PHAT FOILS
PHAT FOILS

PHAT FOILS is our name for the thicker foils that are deployed on some of our fin designs. By making the foils a lot thicker the efficiency of the fin is dramatically improved. Plus on fins that also use our FLIP TIP technology the PHAT FOILS allow for a much better transition from the blade of the fin into the tips.

Currently, these foils are only available on our custom fins, but some of the newer designs that will go into production this year will feature these foils.

BASES

There are a lot of different fins systems available in the market, many with their own unique base styles. HANALEI FINS supports the three primary bases - GEARBOX (our base is also compatible with ProBox), DUAL TAB, and FUTURES, for side fins, and the REGULAR base for normal longboard fin boxes.

GEARBOX
GEARBOX Base
GEARBOX Base

The GEARBOX base is used in our own fin system GEARBOX, it features a full base for a solid feel and greater strength. The GEARBOX base also features vee notches where the screws land that allow the fin base to be forced down into the box when tightened, creating a compression fit.

The GEARBOX base is also compatible with the ProBox Fin System.

DUAL TAB
DUAL TAB Base
DUAL TAB Base

The DUAL TAB base is widely available due to the large number of boards with the twin plugs installed. The DUAL TAB base also fits in the GEARBOX fin box. These bases are designed to break under load and therefore tend not to be very durable, breaking at inopportune times. the other problem with these bases is the tendency to flex in the base instead of the fin, this is due to the narrow interface between the fin base and the box.

FUTURES

FUTURES Deep FUTURES Deep

The FUTURES fin base is a lot longer than other bases due to the design of their box. Due to the nature of the fin box design the cant angle is built into the base of the fins instead of into the box. This makes it really complicated making fins for this system, especially if they are custom fins as the can angle has to bee machined into the base of the fin. Fit is critical for these bases as there is no means to tighten them if they are loose.

These bases can also be a lot heaver due to the fact that they are almost double the length of a GEARBOX or DUAL TAB base. This is why you will commonly see these bases heavily machined in order to lighten them up.

REGULAR
REGULAR Base
REGULAR Base

The REGULAR base is the standard longboard center fin style base. Designed to fit in most modern center boxes.

CNC MACHINING

CNC Machining
CNC Machining

Our newest fin construction methodology uses a CNC machine to create fins out of solid fiberglass panels. The method is the closest we can get to our hand foiled fins. The process involves making a sample fin, which is then digitized into a 3D file. This file is then used to generate code that drives the CNC machine, allowing it to reproduce exact copies of the sample fin.

The process involves first laying up panels of solid fiberglass that are then placed in the machine. The thickness of the panels varies depending on the size and thickness of the fin. One side of all the fins on the panel is machined first. Then the panel is flipped over and the other side is machined. It is a slow process but it produces precise fins.

As these are exact copies of the original they have the same flex and strength characteristics!

RTM MOLDING

RTM molding is one of the most predominant methods for molding fins. It stands for Resin Transfer Molding. The fabrics and core that make up the fin are laid dry into a mold. The mold is then closed and a vacuum is used to draw resin through the mold, wetting out the materials in the process. The use of a vacuum also draws all the air out of the laminate eliminating air bubbles.

RTM molding is a lot more cost effective and less wasteful than the standard method of foiling a fin out of a solid panel of fiberglass. Because a mold is used it also makes it easier to manufacture more complex shapes in a consistent manner.

MATERIALS

Fins can be made out of a wide range of materials, but these are some common standard materials, with fiberglass being the most prominent one. RTM molded composite fins use a combination of these materials.

FIBERGLASS
Fiberglass
Fiberglass

Fiberglass forms the bulk of a fin construction and is applied either side of the core material in our HRD-KORE construction method. The typical fin can have as many as 27 layers of fiberglass to provide strength and some flex.

Custom fins are made out of panels that are built into solid sheets of fiberglass and resin. The number of layers can vary from 30 to 40 layers. This is the standard material for hand foiled fins.

CARBON FIBER
Carbon Fiber
Carbon Fiber

Carbon fiber is very strong and stiff for its weight making it perfect for base stiffening. Employed in the base area of the fin to add stiffness and strength, it is applied to both sides of the fin as an outside layer that is visible in the finished product.

SORIC
SORIC Fabric
SORIC Fabric

Soric® is a conformable flow media for resin infusion. This product features unique hexagonal flow channels across a carrier sheet that create a steady, even resin front. Forms the core for the fin and reduces weight by reducing the layers of fiberglass needed to construct the fin.

G-10
G-10 Fiberglass
G-10 Fiberglass

G-10 glass cloth reinforced epoxy natural is typically a yellowish to light green color. The most versatile all-around laminate grades are continuous glass woven fabric impregnated with an epoxy resin binder. These panels are made under high pressure so there is no air in the panel and the resin to fiber ration is very high. This makes for an incredibly strong panel.

Because these panels are manufactured it makes it a lot simpler for a fin manufacturer as one simply purchases the panels and then cuts fins out of it as needed. The panels are a lot more expensive than a standard fiberglass panel, but worth it for the strength.

We are starting to use pieces of G10 embedded int he bases of our HRD-KORE fins in order to strengthen the base. This is only done with the DUAL TAB bases as they have a tendency to snap under load and are very hard to make strong enough. Adding the G10 makes them a lot stronger.

Fin Primer

Understanding fin placements

At best fin setup and placement is more art than science! This information might help explain some of the characteristics of fin placements and selections.

The beauty of an adjustable fin system is that you can go out and experiment for yourself to verify what effect a change in fin placement or template can have on the overall performance of a board.

Terminology

Understanding common terms

This primer will use some terminology that is best explained up front so that we are all speaking the same language.

TERMDESCRIPTION
fin triangle or CLUSTERthis is the grouping of the fins, whether it be a thruster, quad, or 2+1, it refers to the entire fin layout.
fin setupthis is position of the entire fin cluster as a unit, either all forward all back, spread apart, grouped together, etc.
cantalso referred to as fin angle, is the amount by which the side fins are leaning out from the centerline of the surfboard, bottom up.
toe-inthis is the amount that the front of the fin boxes are pointed in (toed in) from the centerline of the box towards the stringer.
fore ’n’ aftthis is the position of the fin in the box forward or backwards along the length of the board.
spread fin CLUSTERthis is where all the fins in the cluster are spread as far apart as possible, side fins all the way forward, center fin all the way back, this generally makes the board stiffer. For quads the fins are spread as far apparent as the box adjustment will allow.
tight fin CLUSTERthe opposite of the spread fin cluster, typically side fins all the way back and center fin all the way forward, makes the board looser and more pivotal. For quads the fins are pushed as close together as the box adjustments will allow, front fins all the way back, back fins all the way forward.
THRUSTER setupa thruster setup consists of a set of side fins and a center fin, with the most common setup featuring fins that are all the same height.
QUAD setupa quad setup consists of a two sets of side fins, with the most common setup featuring a larger set of fins in front of a smaller set. The placement of these two sets relative to each other can vary widely, but our preference is for them to be close together.
reverse QUAD setupa reverse quad setup consists of two sets of side fins, with the smaller set of fins in front of a larger set. The placement of these two sets relative to each other can vary widely, but our preference is for them to be close together. This is a term we coined to describe this setup arrangement.
TWINZER setupa twinzer setup consists of a two sets of side fins, with a small set of canard-style fins in front of a much larger set. The placement of these two sets relative to each other is typically very tight to allow the canard fin to serve as a transition fin to the larger fin. The canard fins typically have additional cant built into the base in order to have more cant than the boxes typically provide.
5FIN setupa 5FIN setup is simply a quad setup with the addition of a center box, this allows the board to be ridden as either a quad or a thruster, or with all five fins.
2PLUS1 setupa 2+1 setup consists of a set of side fins, and a much larger center fin, most commonly placed in a regular longboard center box. The side fins are commonly very small in relationship to the size of the center fin, but the heights can vary.
SINGLE fin setupsingle fins are either setup in a regular longboard center box, or glassed on to the bottom of the board. One fin setup on the board centerline.

SETUP DETAILS

Understanding characteristics of different setups

Below is just a small sampling of the more obvious combinations, there are many more in between or with subtle variations. The intent has been to provide a little insight into the more general characteristics of fin placement.

Obviously, the position and cant of the fins are very important and greatly affect the performance of a surfboard. The smallest change can sometimes have a dramatic effect on the board, but it is not a magic bullet, sometimes the opposite effect can occur. Fin setup is just one piece in a complex dynamic system of shapes and curves that make up a surfboard.

Each board is different, as is each surfer, so any changes could have different results depending on the board and the surfer!

The information provided above is applicable to a 2+1 fin setup, except in that type of setup the size of the center fin has a more heavily weighted effect on the cluster. The smaller the center fin the more it will perform like a thruster. Placement of the center fin is going to be by far the more controlling aspect of the performance of a 2+1 setup.

Of course there are other factors that can affect fin setup, the size and shape of the fin, even the foiling of the fin. Whether all of the fins in the cluster are the same size, or not. We believe the beauty of an adjustable system is that it allows the surfer to experiment for themselves to determine what works for them and to help them learn the significance of being able to adjust the fin setup on a surfboard.

CLUSTER SETUPCHARACTERISTICSCONDITIONS
spread fin CLUSTERlonger turning arc, more common on longer boards or gunslarger faster waves, situations where a gun would more likely be used.
tight fin CLUSTERshorter turning arc, the common setup for smaller thrusterswide range, depending on skill and the shape of the board.
fin CLUSTER forwardlooser, shortest arc, less holdpivotal surfing on small to medium waves.
fin CLUSTER normalloose with control, typically the position designed by the shaperversatile wide range of conditions.
fin CLUSTER backmore control, more projection, bigger, tube/pocket wavesonce again typical for situations for a gun.
more fin cantlooser with less drive, requires more turning to generate speedsmall to medium surf.
less fin cantstiffer with more drive, bigger, faster hollow surfcommonly used in twin fins, guns or tow-in boards.

ILLUSTRATED TERMS

Visualizing setups

The renderings in this section show illustrations for some of the terms used in the fin setup discussion.

Hopefully, these will provide a visual guide to some of the terminology.

A4C Banner
FIN CLUSTER

Shows what is referred to as a fin cluster, which is the combination of all of the fins in the layout.

Cluster Rear View
Cluster Rear View

Another view of the fin cluster from the rear of the board, showing the cant angles of the fins in the cluster. When talking about fins this is the most common view used to refer to the left and right fins.

CANT Angle
Cant Angle

Shows how the cant angle is measured. With the GEARBOX fin system the cant angle is built into the box. The correct cant angle needs to be selected before installation.

XPD2 Banner
Toe-in

Toe-in of the boxes, is another critical value, shown in this drawing.

This is the distance that the boxes are pointed in towards the stringer, from the box centerline. In quad setups this can vary from the front to the back fins.

A4C-500CK Center
Spread Fin Cluster

A spread fin cluster is where the fins are spread as far apart from each other as possible. For a thruster this means the side fins are as far forward as possible and the center fin as far back as possible. For quads the front fins are as far forward as possible, and the back fins as far back as possible.

A4C-500CK Center
Tight Fin Cluster

A tight fin cluster is where the fins are pushed as close together as possible. For a thruster this means the side fins are as far back as possible and the center fin as far forward as possible. For quads the front fins are as far back as possible, and the back fins as far forward as possible.

To find out more, or to get answers to questions

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